How to Prevent Laptop from Suspending When on Lock Screen

My laptop, running Ubuntu 20.04.4 LTS goes into suspend mode almost instantly after I lock the screen with Meta - L. I would like to stop this behaviour so the laptop stays awake, but idle on the lock screen, with the lid open.

I've experimented with the settings in Power, and Privacy > Screen Lock, but even with Blank Screen Delay set to Never in Screen Lock, and Blank Screen set to Never in Power it still shows exactly the same behaviour.

I'm assuming this isn't possible through the GUI, but hoping there is a config file somewhere I can edit to get the desired effect.